ChemInform Abstract: A Concise Total Synthesis of (.+-.)-cis- and (.+-.)-trans-Clavicipitic Acids by Combinatorial Use of Directed Lithiation and Fluoride Ion- Induced Elimination-Addition Reaction of 1-(Triisopropylsilyl)gramine Derivatives.

ChemInform ◽  
2010 ◽  
Vol 28 (14) ◽  
pp. no-no
Author(s):  
M. IWAO ◽  
F. ISHIBASHI
2006 ◽  
Vol 84 (10) ◽  
pp. 1226-1241 ◽  
Author(s):  
Peter Wipf ◽  
Michel Grenon

Our recent progress toward the synthesis of the furanocembranolide lophotoxin (1) is disclosed. Strategies for the stereoselective incorporation of the C13 stereocenter by a catalytic desymmetrization of a cyclic meso-anhydride, as well as a novel 1,6-addition reaction of organocuprates to unsaturated [1,3]dioxin-4-ones are discussed. Preliminary results on the development of a rhodium-catalyzed asymmetric 1,6-addition reaction are also mentioned. Finally, modifications of a previously reported transition-metal-catalyzed cyclization reaction involving α-propargyl β-keto esters allow furan ring formation either under thermal conditions or by microwave irradiation.Key words: 1,6-addition, organocuprates, catalytic desymmetrization, furan cyclization, microwave.


Synlett ◽  
2018 ◽  
Vol 29 (09) ◽  
pp. 1203-1206 ◽  
Author(s):  
Hyoungsu Kim ◽  
Hosam Choi ◽  
Kiyoun Lee

A concise total synthesis of (±)-mesembrine has been successfully accomplished in seven steps and 24% overall yield from commercially available 3-ethoxy-2-cyclohexen-1-one. Central to the assembly of the skeleton of mesembrine are a Johnson–Claisen rearrangement for the formation of the benzylic quaternary stereocenter and direct allylic oxidation to generate the substrate for the amidation/transannular aza-conjugate addition reaction.


Tetrahedron ◽  
1997 ◽  
Vol 53 (15) ◽  
pp. 5593-5608 ◽  
Author(s):  
Cesare Gennari ◽  
Daniela Moresca ◽  
Anna Vulpetti ◽  
Gilles Pain

Synlett ◽  
2019 ◽  
Vol 31 (01) ◽  
pp. 7-12 ◽  
Author(s):  
Ye Zhang ◽  
Lei Zhang ◽  
Xiangbing Qi

Indole-fused tetracyclic ring systems containing nitrogen atoms are common core skeletons of many indole alkaloids such as sarpagine, macroline, and ajmaline. Efficient and stereoselective construction of these ring systems can promote the development of the corresponding alkaloid syntheses. In this article, we briefly summarize our current progress toward the application of the aza-Achmatowicz reaction and indole nucleophilic addition reaction cascade for the first asymmetric total synthesis of the macroline-type indole alkaloid (–)-Alstofolinine A. Our synthetic strategy is based on furan oxidation/rearrangement and proceeds from easily accessible materials such as indole and furan derivatives.


Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2669-2672
Author(s):  
Kai Dong

The first total synthesis of kukoamine B bimesylate was completed from 1,4-diaminobutane dihydrochloride in 12 steps with a 11.4% overall yield, and all the steps could be carried out at a kilogram scale. The cyano groups were used as the precursor of amino groups to avoid the competitive reaction delicately. The aza-Michael addition reaction, amidation and hydrogenation of the cyano group sequence was streamlined as a general approach towards the synthesis of polyamine structures.


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